Pickling apparatus



April 30, 1963 E. A. LAINE PICKLING APPARATUS 2 Sheets-Sheet 2 Filed Dec. 15, 1960 INVENTOR Edward A; Luine -J PM M NQ ow L vHH ATTORNE:

United States Patent 3,087,505 PICKLING APPARATUS Edward A. Laine, Leechbnrg, Pa., assignor to Allegheny Ludlum Steel Corporation, Breckenridge, Pa., a corporation of Pennsylvania Filed Dec. 15, 1960, Ser. No. 76,034 16 Claims. (Cl. 134105) This invention pertains to apparatus which is useful in the treatment of materials in the form of strip and in particular to apparatus for use in the descaling of materials in a fluid reagent.

Heretofore, materials in the form of strip have been treated with a fluid reagent in any number of ways. One of the most common of the various apparatus utilized consisted of a tub containing a fluid reagent, for example, an acid pickling bath. Where the fluid reagent was of a highly reactive or corrosive nature, with respect to either the apparatus used or the material being treated, suitable precautions had to be observed. The fluid reagent was usually contained within a tub, and material was drawn through the tub. This is espectially true where the over-all treatment was of a continuous nature. Illustrative of the foregoing is the apparatus used in the caustic or acid picking of metals and alloys, for example, steel.

This apparatus consisted principally of a tub containing the fluid reagent and means for supporting the material, usually in the form of strip, adjacent the ends thereof. Means for immersing the strip within the bath of the fluid reagent were also provided. These latter means have usually taken the form of one or more spaced immersion rolls which were usually of a sufliciently large diameter to enable the roll shafts and hearings to remain out of the bath of the fluid reagent, yet hold the strip below the surface of the bath as illustrated for example in U.S. Patent No. 2,862,839. Consequently, a segment of the immersion roll was submersed in the fluid reagent and the remainder was continuously re-exposed to the air. Where the bath contains a reagent of a molten salt or other strong chemical pickling solutions, for example, a nitric acid-hydrofluoric acid or a sulfuric acid bath, that portion of the roll which is exposed to the air is continuously rescaled, and upon rotation about its shaft, that portion of the roll is then descaled when it re-enters the bath. This continuous scaling and descaling of the immersion roll results in scale deposits upon the surface of the strip material being descaled or, in the alternative, an uneven descaling on the top surface of the strip being processed.

Moreover, when these large diameter rolls are used in descaling certain metals, such as titanium, or metals that are farther apart in the electro-chemical series from the material of which the descaling vessel is made, it has been found that an electrolytic action is established 'between the strip being descaled and the immersion rolls with the salt bath being the electrolyte. This action causes minute widely scattered pimples to form on the surface of such a steel immersion roll. Since on a conventional large diameter immersion roll there is a heavier layer of more electrically insulated scale between the strip and the immersion roll, these pimples at times pierce this insulation boundary and cause an electrical path which preferentially pits or otherwise disrupts the strip surface. In addition, because these conventional steel immersion rolls are of such a large diameter, of

3,087,505 Patented Apr. 30, 1963 necessity they are subject to more inertia. Thus, during strip speed changes, slippage occurs between the roll and the strip thereby marring the surface. This is further complicated when the fluid reagent is a molten caustic bath which acts as a lubricant between the immersion roll and the material being treated. The apparatus of the present invention corrects these faults by providing a small diameter roll of low inertia which is completely submersed Within the descaling bath.

An object of the present invention is to provide apparatus for use in the treatment of material without marring the surface of said material.

Another object of this invention is to provide an apparatus which will hold the material submersed within a fluid reagent without marring the surface thereof.

A more specific object of this invention is to provide apparatus having a small diameter immersion roll which is completely immersed within a chemical descaling bath and which may be quickly changed without stopping the descaling process.

These and other objects of this invention will become apparent to one skilled in the art when taken in conjunction with the following description and the drawings in which:

FIGURE 1 is a drawing illustrating a schematic arrangement in partial section of the apparatus of the present invention;

FIG. 2 is a view in section taken along the line :IIII of PEG. 1;

FIG. 3 is a View of the sinker unit in partial section;

FIG. 4 is a view in partial section taken along the line IVIV of FIG. 3, and

FIG. 5 is a view in partial section of the indexing mechanism.

Referring now to the drawings and FIGS. 1 and 2 in particular, this invention is illustrated by referring to a tub shown generally at 10 in which the strip material 12 is to be treated. The tub 10 is formed from a bottom member 14, side walls 16 and end walls 18 which are so disposed as to provide a container for a fluid reagent 20. As illustrated in FIGS. 1 and 2, the tub 10 may also be provided with a liner 22 formed of a material which will not react with the fluid reagent 20 contained within the tub 10. The tub 10 may also be provided with a means 24 for controlling the temperature to the bath 20 contained within tub 10. This is most conveniently accomplished by means of radiant heater tubes or electric elements which are disposed externally or internally along the side walls 16 and end walls 18, and where desired, adjacent the bottom 14 of the tub 10. The fluid reagent 20 can thus be a fused salt bath or an acid bath of the nitric-hydrofluoric acid type or sulfuric acid type. In any event, any desirable fluid reagent may be disposed within the tub 10 and maintained at a given temperature range.

Preferably, entrance and exit support rolls 26' are mounted adjacent the end walls 18 of the tub and where desired, guide or wiper rolls 28 may be interposed intermediate the entrance and exit support rolls 26 for supporting, wiping or guiding the strip material 12 into and out of the fluid reagent 20 contained in tub 10. The strip material 12 is placed or fed over the support rolls 26 and under the guide or wiper rolls 28 and is held submersed beneath the surface of the fluid reagent 20 by means of the sinker unit shown generally at 30 as more clearly illustrated in FIG. 1.

The sinker unit 30 as shown in FIG. 2 comprises a shaft 32, roll supporting end plates 34 carried thereon and at least a pair of spaced small diameter rolls shown generally at 36, each component of which will be more fully described hereinafter. The sinker unit 30 may be conveniently mounted on a pair of upwardly extending support columns 38 as illustrated in FIG. 2, each of said support columns being disposed adjacent the side walls 16 of the tub in an aligned relation in a vertical plane perpendicular to the direction of movement of the strip 12 through the tub 10, or, if preferred, the sinker unit 30 may be mounted on the top rim of the tub 10. A pillow block 40 is conveniently mounted on the upper extremity of each of the upwardly extending support columns 38 or tub rim to which the sinker unit 30 may be rotatably secured. Each pillow block 40 comprises a base 42 and an upwardly extending housing 44 with a bushing (not shown) contained therein and disposed to receive one end of the shaft 32 to be rotatably secured therein.

The support shaft 32 of the sinker unit 30 is provided with bearing surfaces 46 near each end thereof as more clearly illustrated in FIG. 3. Each of the bearing surfaces 46 of the shaft 32 is disposed to be received by the bushing (not shown) in the pillow block 40 and rotatably secured therein. One end of the shaft 32 of the sinker unit 30 is also provided with a keeper groove 48 adjacent the bearing surface 46 and a shaft extension nipple 50, the keeper groove 48 and a shaft extension nipple 50 being disposed near the outer extremity of one end of the shaft adjacent the bearing surface 46. A keeper plate 52 is disposed to be seated in the keeper groove 48 and is secured by means of bolts (not shown) to the pillow block 42 thus rotatably securing the shaft 32 of the sinker unit 30 in an operative position. The shaft 32 is also provided with a pair of keyways 54 intermediate the bearing surfaces 46 and a keyway 56 in the shaft extension nipple 50, each of which will be explained more fully hereinafter.

A pair of roll supporting end plates 34 is disposed to be carried by the shaft 32 intermediate the bearing surfaces 46 of the sinker unit 30. Each of the roll supporting end plates 34 comprises a hub 58 and radial web members 60, said hub 58 being provided with a keyway 62 which complements keyway 54. A key 64 is interposed within the complementing keyways 54 and 62, respectively, thus securing the roll supporting end plate 34 to the shaft 32 for movement with the shaft 32. The hub is also provided with an opening for the insertion of a set screw or pin 66 to secure the hub 58 to the shaft 32. The roll support end plates 34 are provided with an annular collar 68 which is disposed near each of the outer extremities of the roll support end plates 34, said annular collar 68 being secured to the roll support end plate 34 by means of weldment 70. While in the embodiment illustrated, the annular collar 68 is welded to the roll support end plate 34, any means of securing the annular collar 68 to the roll support end plate 34 will suflice, for example, weldment 70 may be supplanted by providing the annular collar with a flange, (not shown) and by bolting said flange to the roll support end plate 34. A shaft stub 72 is disposed to be carried by the annular collar 68 and secured therein by means of a pin 74 as illustrated in FIG. 3, said shaft stub 72 being provided with a bearing surface 76, the function of which will be described more fully hereinafter.

A pair of spaced roll members 36 is disposed to extend between the roll support end plates 34 adjacent the outer extremities thereof, and are rotatably secured thereto by means of stub shafts 72. Each of the rolls 36 comprises a roll body 80 which is preferably hollow and is provided with an annular seal 82 adjacent the opposite ends thereof in any suitable manner. Each annular seal 82 is disposed to have a bushing 84 secured therein which is of a sufficient diameter to accommodate the stub shaft 72, thus permitting the free rotational movement of the roll 36 about the oppositely aligned stub shafts 72. It is preferred to have the roll 36 of a suflieiently small diameter so that when the sinker unit 30 is rotated into the hold-down position illustrated in FIGS. 1 and 2, by the selective indexing means shown generally as 86, the immersed roll 36 will remain totally immersed Within the fluid reagent 20 contained within the tub 10. It will be appreciated that While the embodiment illustrated in FIG. 1 shows the end plates which will accommodate 2 rolls, the end plates 34 may take any desired configuration so as to accommodate any convenient number of rolls, for example, 3, 4, 5, 6 and so on without departing from the spirit or scope of this invention.

The selective indexing means 86 as shown more clearly in FIGS. 3 and 5, comprises a worm gear wheel 88 which is secured to the shaft extension nipple 50 as will be described hereinafter, a worm shaft shown generally at 90 and a worm shaft bracket shown generally at 92. The worm shaft bracket 92 comprises a base member 94, an upwardly extending support member 96 and a cap member 98, said cap member 98 preferably being removably secured to the upwardly extending support member 96. The base member 94 and the cap member 98 are each provided with a passageway 100 and 102, respectively, therethrough, in an aligned relation for rotatably securing the worm shaft 90 in seating engagement therein. The worm shaft 90 comprises a lower shank 104 which is disposed in seating engagement within the passageway 100, worm threads 106, an upper shank 108 which is disposed in rotatable engagement within passageway 102, and a shaft terminal 110 which is disposed to be coupled with a source of rotatable power (not shown).

The worm gear wheel 88 is provided with a keyway 112 which complements the keyway 56 of the shaft extension nipple 50. A key 114 is interposed within the complementing keyways 56 and 112 of the shaft extension nipple 50 and the worm gear wheel 88, respectively, thus securing the worm gear wheel 88 to the shaft extension nipple 50. A keeper plate 116 is disposed to be secured to the end of the shaft extension nipple 50 by means of bolt 118, thus locking key 114 in position within the complementing keyways 56 and 112.

The worm gear wheel 88 is also provided with teeth 120 which are disposed about the periphery of the wheel 88 and cooperate with the threads 106 of the shaft 90 in meshing engagement therewith. A source of rotating power (not shown) is disposed to be coupled with the shaft terminal 110 to rotate the shaft 90 thus rotating the wheel 88 to selectively index the sinker unit 30 into its hold-down position.

The worm gear wheel 88 is provided with teeth 120 which cooperate with and are disposed in meshing engagement with the drive teeth 106 of the worm shaft 90. Any suitable source of power may be applied to the shaft terminal 110 for providing a rotating force to the worm shaft 90 to thus rotate the worm gear wheel 88 to selectively index the sinker unit 30 into its hold-down position.

In operation, the tub 10 is filled to a predetermined height with the fluid reagent 20 and is maintained at a given preselected temperature by means of the radiant heater tubes 24 or other means of heat such as electric elements. The strip material 12 is threaded over the entrance and exit support rolls 26 and under guide rolls 28 and is maintained submersed within the bath 20 by means of the sinker unit 30. As the strip passes through the bath, it is maintained submerged within the fluid reagent 20 by means of the spaced rolls 36 disposed within the reagent turning about the shaft stub 72 which is held between roll supporting end plates 34.

In the event of roll failure, for example, as where a portion of the roll 36 is consumed by the fluid reagent 20, or when it is desired to change the roll 36 that has been immersed for maintenance or inspection purposes, the sinker unit 30 is rotated, for example, 180 to bring the roll 36 at the opposite end of the support plates into engagement with the strip material 12 thus maintaining the strip 12 below the surface of the fluid reagent 20 contained within tub 10. This rotation is accomplished by means of applying turning power to the worm shaft terminal 110, thus rotating the shaft 90 within the bracket 92 to rotate the worm gear wheel 88 through a predetermined arc. The rotation of the worm gear wheel '88 thus turns the shaft extension nipple 50 and the shaft 32 to rotate the roll supporting end plates 34 into the holddown position.

Since the roll 36 is of a sufliciently small diameter that it remains totally submersed within the fluid reagent 20 contained within the tube It the roll body 80 does not become exposed to the atmosphere; thus there is no scaling of the roll body 80 as it rotates about the shaft stub 72 while maintaining the strip 12 submersed within the fluid reagent 20. This also prevents any localized pimpling areas due to the electrolytic action, since there is no way for a localized pitting to occur in the absence of an insulating layer of scale material. Moreover, since the rolls 36 are of a relatively small diameter and the bushings thereof may be exposed to the action of the salt bath, thus providing a continuous lubrication thereof, these rolls are not subject to large inertia and thus during strip speed changes there is little, if any, slippage to thus mar the surface.

I claim:

1. In apparatus for the continuous treatment of strip material, the combination comprising, a tub disposed to contain a fluid reagent to a predetermined height therein, strip entrance and exit supports for maintaining the strip over the tub, at least one sinker unit disposed intermediate said supports for holding the strip material below the surface of the reagent contained within the tub, said sinker unit comprising a rotatable support shaft disposed to extend across the tub adjacent the upper edges thereof, a pair of spaced roll supporting end plates secured to the rotatable shaft, at least two rolls carried by the roll support end plates in spaced relation at the outer extremities thereof and disposed to extend therebetween, each of said rolls having a predetermined diameter so that one of said rolls is wholly submersed in the reagent contained in the tub when the roll support end plates are rotated into operative position to position said one roll in a hold-down position, and means secured to at least one end of the shaft to selectively index the rolls into said operative position.

2. In apparatus for the continuous treatment of strip material, the combination comprising, a tub disposed to contain a fluid reagent to a predetermined height therein, strip entrance and exit supports for maintaining the strip over the tub, and at least one sinker unit for holding the strip material below the surface of the reagent contained within the tub, said sinker unit comprising a pair of pillow blocks, a rotatable support shaft disposed to extend between said pillow blocks, a pair of spaced r-oll supporting end plates secured to the rotaable shaft between the pillow blocks, at least two rolls carried by the roll support end plates in spaced relation near the outer extremities thereof and disposed to extend therebetween, said rolls each having a predetermined diameter so that one of said rolls is wholly submersed in the reagent contained in the tube when the roll support end plates are rotated into operative position to position said one roll in a hold-down position, and means secured to at least one end of the shaft to selectively index the rolls into said operative position.

3. In apparatus for the continuous treatment of strip material, the combination comprising, a tub disposed to contain a fluid reagent to a predetermined height therein, strip entrance and exit supports for maintaining the strip over the tub, at least one sinker unit for holding the strip material below the surface of the reagent contained within the tub, said singer unit comprising a pair of spaced, upwardly extending support columns disposed in an aligned relation adjacent the tub, a support shaft disposed to extend across the tub and rotatably carried by said columns, a pair of spaced roll supporting end plates secured to the rotatable shaft, at least two rolls carried by the roll support end plates in spaced relation near the outer extremities thereof and disposed to extend therebetween, said rolls each having a predetermined diameter so that one of said rolls is wholly submersed in the reagent contained in the tub when the roll support end plates are rotated into operative position to position said one roll in a hold-down position, and means secured to at least one end of the shaft to selectively index the rolls into said operative position.

4. In apparatus for the continuous treatment of strip material, the combination comprising, a tub disposed to contain a fluid reagent to a predetermined height therein, strip entrance and exit supports for maintaining the strip over the tub, at least one sinker unit disposed intermediate said supports for holding the strip material below the surface of the reagent contained within the tub, said sinker unit comprising a pair of spaced, upwardly extending support columns disposed in an aligned relation adjacent the tub, at least one pillow block rigidly secured to each support column, a support shaft disposed to extend between said pillow blocks and rotatably secured therein, a pair of spaced roll supporting end plates secured to the rotatable shaft between the pillow blocks, at least two rolls carried by the roll support end plates in spaced relation near the outer extremities thereof and disposed to extend therebetween, said rolls each having a predetermined diameter so that one of said rolls is wholly submersed in the reagent contained in the tub when the roll support end plates are rotated into operative position to position said one roll in a hold-down position, and means secured to at least one end of the shaft to selectively index the rolls into said operative position.

5. In apparatus for the continuous treatment of strip material, the combination comprising, a tub disposed to contain a fluid reagent to a predetermined height therein, said tub being formed of a bottom, sidewalls and end walls united to contain the reagent within the confines thereof, said tub also containing means to selectively maintain the fluid reagent contained therein within a predetermined temperature range, entrance and exit support rolls rotatably mounted adjacent the end walls of the tub and disposed to suspend the strip material over the tub, at least one sinker unit positioned over the strip intermediate the entrance and exit support rolls and disposed to hold the strip material submersed in the reagent contained Within the tub, said sinker unit comprising a rotatable support shaft, a pair of spaced roll supporting end plates secured to the shaft, at least two rolls carried in spaced relation by the end plates near the outer extremities thereof and disposed to be rotatably secured therebetween, each of said rolls having a predetermined diameter so that one of said rolls is wholly submersed in the reagent contained within the tub when the sinker unit is rotated into operative position to position said one roll in a hold-down position, a worm wheel secured to one end of the support shaft, a worm shaft secured in meshing engagement with the worm wheel, and power means disposed to rotate the worm shaft to selectively index the rolls of the sinker unit into a predetermined operative position.

6. In apparatus for the continuous treatment of strip material, the combination comprising, a tub disposed to contain a fluid reagent to a predetermined height therein, said tub being formed of a bottom, sidewalls and end walls united to contain the reagent within the confines thereof, said tub also containing means to selectively maintain the fluid reagent contained therein within a pre determined temperature range, entrance and exit support rolls rotatably mounted adjacent the end walls of the tub and disposed to suspend the strip material over the tub, at least one sinker unit positioned over the strip intermediate the entrance and exit support rolls and disposed to hold the strip material submersed in the reagent contained within the tub, said sinker unit comprising at least a pair of upward extending support columns disposed in an aligned relation in a vertical plane perpendicular to the direction of the strip movement through the tub, said support columns terminating above the sidewalls of the tub, a support shaft rotatably carried by said columns, a pair of spaced roll supporting end plates secured to the shaft, at least two rolls carried in spaced relation by the end plates near the outer extremities thereof and disposed to be rotatably secured therebetween, each of said rolls having a predetermined diameter so that one of said rolls is wholly submersed in the reagent contained within the tub when the sinker unit is rotated into operative position to position said one roll in a holddown position, a worm wheel secured to one end of the support shaft, a worm shaft secured in meshing engagement with the worm wheel, and power means disposed to rotate the Worm shaft to selectively index the rolls of the sinker unit into a predetermined operative position.

7. In apparatus for the continuous treatment of strip material, the combination comprising, a tub disposed to contain a fluid reagent to a predetermined height therein, said tub being formed of a bottom, sidewalls and end walls united to contain the reagent within the confines thereof, said tub also containing means to selectively maintain the fluid reagent contained therein Within a predetermined temperature range, entrance and exit support rolls rotatably mounted adjacent the end walls of the tub and disposed to suspend the strip material over the tub, at least one sinker unit positioned over the strip intermediate the entrance and exit support rolls and disposed to hold the strip material submersed in the reagent contained within the tub, said sinker unit comprising a pair of pillow blocks, a rotatable support shaft disposed to extend between said pillow blocks and rotatably secured therein, at least one end of said shaft extending through the pillow block a sufficient distance to accommodate an indexing mechanism, a pair of spaced roll supporting end plates secured to the shaft intermediate the pillow blocks, at least two rolls carried in spaced relation by the end plates near the outer extremities thereof and disposed to be rotatably secured therebetween each of said rolls having a predetermined diameter so that one of said rolls is wholly submersed in the reagent contained within the tub when the sinker unit is rotated into operative position to position said one roll in a hold-down position, a worm wheel secured to said one end of the support shaft extending through the pillow block, a worm shaft secured in meshing engagement with the worm wheel, and power means disposed to rotate the worm shaft to selectively index the rolls of the sinker unit into a predetermined operative position.

8. In apparatus for the continuous treatment of strip material, the combination comprising, a tub disposed to contain a fluid reagent to a predetermined height therein, said tub being formed of a bottom, sidewalls and end walls united to contain the reagent within the confines thereof, said tub also containing means to selectively maintain the fluid reagent contained therein within a predetermined temperature range, entrance and exit support rolls rotatably mounted adjacent the end walls of the tub and disposed to suspend the strip material over the tub, at least one sinker unit positioned over the strip intermediate the entrance and exit support rolls and disposed to hold the strip material submersed in the reagent contained within the tub, said sinker unit comprising at least a pair of upward extending support columns disposed in an aligned relation in a vertical plane perpendicular to the direction of the strip movement through the tub, said support columns terminating above the sidewalls of the tub, a pillow block rigidly secured to each of the support columns, a support shaft disposed to extend between said pillow blocks and rotatably secured therein, at least one end of said shaft extending through the pillow block a sufficient distance to accommodate an indexing mechanism, a pair of spaced roll supporting end plates secured to the shaft intermediate the pillow blocks, at least two rolls carried in spaced relation by the end plates near the outer extremities thereof and disposed to be rotatably secured therebetween, each of said rolls having a predetermined diameter so that one of said rolls remains submersed in the reagent contained within the tub when the sinker unit is rotated into operative position to position said one roll in a hold-down position, a worm wheel secured to said one end of the support shaft extending through the pillow block, a worm shaft secured in meshing engagement with the worm wheel, and power means disposed to rotate the worm shaft to selectively index the rolls of the sinker unit into a predetermined operative position.

9. In apparatus for the continuous treatment of strip material, the combination comprising, a tub disposed to contain a fluid reagent to a predetermined height therein, strip entrance and exit supports for maintaining the strip over the tub, at least one sinker unit disposed intermediate said supports for holding the strip material below the surface of the reagent contained within the tub, said sinker unit comprising a rotatable support shaft, a pair of spaced roll supporting end plates secured to the rotatable shaft, at least two rolls carried by the roll support end plates in spaced relation at the outer extremities thereof and disposed to extend therebetween, each of said rolls having a predetermined diameter so that one of said rolls is wholly submersed in the reagent contained in the tub when the roll support end plates are rotated into operative position to position said one rollin a hold-down position, a worm wheel secured to at least one end of the rotatable support shaft, a worm shaft secured in meshing engagement with the worm wheel, and power means disposed to rotate the worm shaft to selectively index the rolls of the sinker unit into a predetermined operative position.

10. In apparatus for the continuous treatment of strip material, the combination comprising, a tub disposed to contain a fluid reagent to a predetermined height therein, strip entrance and exit supports for maintaining the strip over the tub, and at least one sinker unit for holding the strip material below the surface of the reagent contained within the tub, said sinker unit comprising a pair of pillow blocks, a rotatable support shaft disposed to extend between said pillow blocks and rotatably secured therein, a pair of spaced roll supporting end plates secured to the rotatable shaft between the pillow blocks, at least two rolls carried by the roll support end plates in spaced relation near the outer extremities thereof and disposed to extend therebetween, said rolls each having a predetermined diameter so that one of said rolls is wholly submersed in the reagent contained in the tub when the roll support end plates are rotated into operative position to position said one roll in a hold-down position, a worm wheel secured to at least one end of the rotatable support shaft, a worm shaft secured in meshing engagement with the worm wheel, and means disposed to rotate the worm shaft to selectively index the rolls of the sinker unit into a predetermined operative position.

11. -In apparatus for the continuous treatment of strip material, the combination comprising, a tub disposed to contain a fluid reagent to a predetermined height therein, strip entrance and exit supports for maintaining the strip over the tub, at least one sinker unit for holding the strip material below the surface of the reagent contained within the tub, said sinker uni-t comprising a pair of spaced, upwardly extending support columns disposed in an aligned 9 relation adjacent the tub, a support shaft rotatably carried by said columns, a pair of spaced roll supporting end plates secured to the rotatable shaft, at least two rolls carried by the roll support end plates in spaced relation near the outer extremities thereof and disposed to extend therebetween, said rolls each having a predetermined diameter so that one of said rolls is wholly submersed in the reagent contained in the tub when the roll support end plates are rotated into operative position to position said one roll in a hold-down position, a worm wheel secured to at least one end of the rotatable support shaft, a worm shaft secured to at least one end of the rotatable support shaft,

' a worm shaft secured in meshing engagement with the worm wheel, and means disposed to rotate the worm shaft to selectively index rolls of the sinker unit into a predetermined operative position.

12. In apparatus for the continuous treatment of strip material, the combination comprising, a tub disposed to contain a fluid reagent to a predetermined height therein, strip entrance and exit supports [for maintaining the strip over the tub, and at least one sinker unit disposed intermediate said supports for holding the strip material below the surface of the reagent contained Within the tub, said sinker unit comprising a pair of spaced, upwardly extending support columns disposed in an aligned relation adjacent the tub, at least one pillow block rigidly secured to each support column, a support shaft disposed to extend between said pillow blocks and rotatably secured therein, a pair of spaced roll supporting end plates secured to the rotatable shaft between the pillow blocks, at least two rolls carried by the roll support end plates in spaced relation near the outer extremities thereof and disposed to extend therebetween, said rolls each having a predetermined diameter so that one of said rolls is wholly submersed in the reagent contained in the tub when the roll support end plates are rotated into operative position to position said one roll in a hold-down position, a worm wheel secured to at least one end of the rotatable support shaft, a worm shaft secured in meshing engagement with the worm wheel and power means disposed to selectively index the rolls of the sinker unit into a predetermined operative position.

13. In apparatus for the continuous treatment of strip material, the combination comprising, a tub disposed to contain a fluid reagent to a predetermined height therein, said tub being formed of a bottom, sidewalls and end walls united to contain the reagent within the confines thereof, said tub also containing means to selectively maintain the fluid reagent contained therein within a predetermined temperature range, entrance and exit support rolls rotatably mounted adjacent the end walls of the tub and disposed to suspend the strip material over the tub, at least one sinker unit positioned over the strip intermediate the entrance and exit support rolls and disposed to hold the strip material submersed in the reagent contained within the tub, said sinker unit comprising :a rotatable support shaft disposed to extend across the tub adjacent the upper edges thereof, a pair of spaced roll supporting end plates secured to the shaft, at least two rolls carried by the end plates in spaced relation near the outer extremities thereof and disposed to be rotatably secured therebetween, each of said rolls having a predetermined diameter so that one of said rolls is wholly submersed in the reagent contained within the tub when the sinker unit is To tated into operative position to position said one roll in a hold-down position, and means secured to at least one end of the shaft to selectively index the rolls into said operative position.

14. In apparatus for the continuous treatment of strip material, the combination comprising, a tub disposed to contain a fluid reagent to a predetermined height therein, said tub being formed of a bottom, sidewalls and end walls united to contain the reagent within the confines thereof, said tub :also containing means to selectively maintain the fluid reagent contained therein within a predetermined temperature range, entrance and exit support rolls rotatably mounted adjacent the end walls of the tub and disposed to, suspend the strip material over the tub, at least one sinker unit positioned over the strip intermediate the entrance and exit support rolls and disposed to hold the strip material submersed in the reagent contained within the tub, said sinker unit comprising at least a pair of upward extending support columns disposed in an aligned relation in a vertical plane perpendicular to the direction of the strip movement through the tub, said sup port columns terminating above the sidewalls of the tub, a support shaft disposed to extend across said tub and rotatably carriedby said columns, a pair of spaced roll supporting end plates secured to the shaft, at least two rolls carried by the end plates in spaced relation near the outer extremities thereof and disposed to be rotatably secured therebetween, each of said rol-ls having a predetermined diameter so that one of said rolls is wholly submersed in the reagent contained within the tub when the sinker unit is rotated into operative position to position said one roll in a hold-down position, and means secured to at least one end of the shaft to selectively index the rolls into said operative position.

15. In apparatus for the continuous treatment of strip material, the combination comprising, a tub disposed to contain a fluid reagent to a predetermined height therein, said tub being formed of a bottom, sidewalls and end walls united to contain the reagent within the confines thereof, said tub also containing means to selectively maintain the fluid reagent contained therein within a predetermined temperature range, entrance and exit support rolls rotatably mounted adjacent the end walls of the tub and disposed to suspend the strip material over the tub, at least one sinker unit positioned over the strip intermediate the entrance and exit support rolls and disposed to hold the strip material submersed in the reagent contained within the tub, said sinker unit comprising a pair of pillow blocks, a rotatable support shaft disposed to extend across said tub and between said pillow blocks and rotatably secured therein, at least one end of said shaft extending through the pillow block a sufficient distance to accommodate an indexing mechanism, a pair of spaced roll supporting end plates secured to the shaft intermediate the pillow block-s, at least two rolls carried by the end plates in spaced relation near the outer extremities thereof and disposed to be rotatably secured therebetween, each of said rolls having a predetermined diameter so that one of said rolls is wholly suhmersed in the reagent contained within the tub when the sinker unit is rotated into operative position to position said one roll in a hold-down position, and means secured to at least one end of the shaft to selectively index the rolls into said operative position.

16. In apparatus for the continuous treatment of strip material, the combination comprising, a tub disposed to contain a fluid reagent to a predetermined height therein, said tub being formed of a bottom, sidewalls and end walls united to contain the reagent within the confines thereof, said tub also containing means to selectively maintain the fluid reagent contained therein within a predetermined temperature range, entrance and' exit support rolls rotatably mounted adjacent the end walls of the tub and disposed to suspend the strip material over the tub, at least one sinker unit positioned Over the strip intermediate the enrance and exit support rolls and disposed to hold the strip material sub-mersed in the reagent contained within the tub, said sinker unit comprising at least a pair of upward extending support columns disposed in an aligned relation in a vertical plane perpendicular to the direction of the strip movement through the tub, said support column-s being adjacent to and terminating above the side walls of the tub, a pillow block rigidly secured to each of the support columns, a support shaft disposed to extend between said pillow blocks and rotatably secured therein, a pair of spaced roll supporting end plates secured to the 1 1' shaft intermediate the pillow blocks, at least two rolls carried by the end plates in spaced relation near the outer extremities thereof and disposed to be rotatably secured therebetween, eachof said rolls having a predetermined diameter so that one of said rolls remains submersed in the reagent containedwithin the tub when the sinker unit is rotated into operative position to position said one roll in a hold-down position, and means secured to at least one operative position.

References Cited in the file of this patent UNITED STATES PATENTS Trautman May 9, 1944 Van Der Mei Jan. 18, 1949 Lorig Sept. 7, 1954 Spence Mar. 13, 1956 Shank Aug. 22, 1961 FOREIGN PATENTS France Sept. 25, 1902 

1. IN APPARATUS FOR THE CONTINUOUS TREATMENT OF STRIP MATERIAL, THE COMBINATION COMPRISING, A TUB DISPOSED TO CONTAIN A FLUID REAGENT TO A PREDETERMINED HEIGHT THEREIN, STRIP ENTRANCE AND EXIT SUPPORTS FOR MAINTAINING THE STRIP OVER THE TUB, AT LEAST ONE SINKER UNIT DISPOSED INTERMEDIATE SAID SUPPORTS FOR HOLDING THE STRIP MATERIAL BELOW THE SURFACE OF THE REAGENT CONTAINED WITHIN THE TUB, SAID SINKER UNIT COMPRISING A ROTATABLE SUPPORT SHAFT DISPOSED TO EXTEND ACROSS THE TUB ADJACENT THE UPPER EDGES THEREOF, A PAIR OF SPACED ROLL SUPPORTING END PLATES SECURED TO THE ROTATABLE SHAFT, AT LEAST TWO ROLLS CARRIED BY THE ROLL SUPPORT END PLATES IN SPACED RELATION AT THE OUTER EXTREMITIES THEREOF AND DISPOSED TO EXTEND THEREBETWEEN, EACH OF SAID ROLLS HAVING A PREDETERMINED DIAMETER SO THAT ONE OF SAID 